This invention relates to disposable diapers. More particularly, this invention relates to disposable diapers adapted to be secured in place by adhesive tabs.
Disposable diapers provide substantial advantages in convenience over diapers intended to be laundered and reused, particularly when they are used away from home. In recent years, many different disposable diapers have been proposed and some have been successful in the marketplace. Typical disposable diaper structures comprise a moisture-retaining layer of high liquid-holding capacity and a moisture-impervious backing sheet therefor, generally made of a plastic film such as polyethylene film or the like. Typical disposable diaper structures are shown in U.S. Pat. No. 3,612,055 to Mesek et al. and in U.S. Pat. No. Re. 26,151 to Duncan et al.
As may be seen from the above-cited patents, it is desirable to obviate the problems that are inherent in closure systems which utilize extraneous fasteners such as safety pins, snaps and zippers. To this end adhesive closure systems have presented acceptable solutions.
In order to protect the adhesive surfaces of the tape tabs, usually a cover strip having a release surface is applied over these adhesive surfaces for subsequent removal when the diaper is about to be used. However, such tabs usually project beyond the confines of the diaper to a considerable extent and interfere with the efficient manufacture and packaging of the diaper.
In an attempt to solve the foregoing problems, U.S. Pat. No. 3,646,937 to Gellert teaches a fastening tab which is provided with a release surface permanently bonded to the inside surface of the diaper. One of the drawbacks of the Gellert arrangement is that the release surface is on the inside surface of the diaper where it can possibly come into contact with an infant's tender skin when the diaper is used.
U.S. Pat. No. 3,750,669 to DeLuca shows a fastening tape provided with an adhesive end portion which extends beyond a cover strip for the tape and which is attached to a diaper inner covering or facing. However, such an adhesive end portion, when attached to a fibrous, non-woven facing fabric, may tear the facing fabric upon separation therefrom.
U.S. Pat. No. 3,776,234 to Hoey proposes to fold the tab over on itself at the diaper's edge and to adhesively attach a portion of the folded-over tab segment to an inwardly-folded margin of the diaper backing sheet in order to keep the tab flat against the diaper and thus from interfering with the manufacturing machinery and with the subsequent folding and packaging operations. This requires that the edge of the diaper backing sheet be folded over to present an attachment surface at the front or inside face of the diaper, and a relatively involved tab design is necessary for this purpose. Also, undesirable tearing of the diaper facing fabric may result if such a tab is inadvertently adhesively attached to the facing fabric of the diaper during manufacture.
U.S. Pat. No. 3,874,386 to Kozak discloses a tab fastener having a fixed end secured to a backing sheet, an opposite releasable end, and a middle segment carrying a release agent. The tab fastener is folded to superpose the releasable end segment and the middle segment over the fixed end, with the releasable end being releasably secured to the middle segment. Such a fold configuration restricts the distance at which the fixed end can be spaced from a longitudinal margin of the diaper and also requires that a substantial portion of the tab fastener itself by non-adhesive so as to accommodate the entire tacky area of the releasable free end. The non-adhesive portion, of course, is not available for securement.